Machine for routing stair stringers



June 9, 1931. c. MACKAY 1,808,962

V MACHINE FOR ROUTING STAIR STHINGERS Filed Sept. 18, 1950 4 Sheets-Sheet 1 [05%666 z Maw/pm M 74% g; 5

June 9, 1931. MACKAY 1,808,962

7 MACHINE FOR ROUTING STAIR STRINGERS Filed Sept. 18, 1930 4 Sheets-Sheet 2 June 9, 1931. 'G. MACKAY 1,808,962

momma FOR 1101mm sum surnmenns V Filed Sept. 18, 1950 4 Sheets-Shae) 4 MM, Q5275:

Patented June 9, 1931 UNITED rattan GEORGE MACKAY, F JACKSON, MICHIGAN MACHINE FOB RGUTENG- STATE. STRINGERS Application filed September 18, 1930. Serial No. 482,781.

This invention relates to a machine for cutting the tread and riser channels in the sides of stair stringers.

The purpose of the invention is mainly to provide a construction which is suitable for routing operations in stair stringers to meet the requirements of variation in the pitch of the stairs and the height of floors, so that the tread and riser channels may 1 be properly cut at the required angles with reference to the slope of the stringers, and to meet requirements as to distance between treads in different arrangements of flights according to the variable distances between floors.

ther objects of the invention are to provide improvements in setting mechanism for machines of this class to determine the distance between treads for a given stairway,

the angle at which the router operates with reference to the slope of the stairway, and to provide a machine which will rout a pair of stringers at the same time.

The objects of the invention are accomplished by means of a construction as illustrated in the drawings, in which:

Figure 1 is a plan view, partly in section and partly broken away, of the improved routing machine.

Fig. 2 shows the machine in front elevation and partly broken away.

Fig. 8 shows the routing machine in end elevation.

Fig. 4 is a sectional detail taken on the line H of Fig. 1.

Fig. 5 is a fragmentary plan view, partly broken away, showing a stair stringer as it would appear in the machine during the routing operation.

Fig. 6 is a fragmentary plan of a stair stringer showing by dotted lines, paths of travel of the routing tools.

Fig. 7 is a fragmentary bottom edge view of the stringer shown in Fig. 6.

Fig. 8 is a fragmentary sectional detail of a completed stairway.

The general arrangement ofthis machine is a long table-like structure for supporting in horizontal position and spaced apart vertically, a pair of stair stringers, and motor driven routers for simultaneously cutting the tread and riser channels in the pair of stringers. The routing tools are preferably driven by electrical motors so mounted as to be shiftable predetermined distances longitudinally of the machine, and likewise angularly in unison around a common center for regulating the pitch of stairs, and individually are slidable for making the cut, and individually are shiftable around an off-side vertical pivot for varying the Width of the cut channel from end to end thereof in order that the channel may be properly formed for receiving the wedges which hold the treads and risers of the stairway tightly in the stringers.

Referring to the drawings, the routing machine comprises a supporting frame structure '1, a. table top 2, curved brackets 3 extending upwardly and over the table top. The table top supports on its upper surface one of the stringers, indicated at 4-, Fig. 3, clamped to the table top against a shoulder 5 thereon, by clamp 6. The companion stair stringer? is shown carried by clamp constructions 8 and 9, carried by brackets 8. A pair of motors, 10 and 11, are slidably supported on pairs of horizontally disposed rods 12, and the shaft of each motor extends beyond its bearings, and is provided at its ends with chucks 13 for carrying routing tools 14. The rods 12 pass through apertures in frame parts 15 of the motors, and are supported in a U-shaped frame 16, pivotally mounted at one end on vertical posts 17 and at the opposite end having tongues 18 extending into curved channels 19, Fig. 5, of relatively fixed guide members 20. The routing tool motors are slidable on the rods 12, so that the motors may be pushed into engagement with and drawn away from the articles worked upon, and for this purpose the motor frames carry handles 21.

In cutting the channels 22 and 23 in the stair stringers, the motor supporting. frame is swung around the pivot post 17 until it engages one of the pins 24 or 25, and the motor with the rotating routing tools thereon is pushed inwardly until the part 26 of the motor frame engages the end member 27 of frame 6, or adjustable means thereon for limiting the travel of the motor in this direction. The motor unit and its supporting frame are then swung around pivot 17 until stopped by one of the pins 2% and when in the return direction a ong the rods 12. lhe channel 22 or 23 i do cut by this operation is accordingly w'der as the lower side of the stringer than at the inner end of the cut.

lhe vertical posts 17, around which the motor units swing, extend upwardly from a ortin plate 28 for the routing units, and e is ivotally mounted on a post 29. angement, both routing units ing in unison around the post 29, purpose of varying the angle of the wi reference to the edges of the maintaining the risers and the router is drawn rs wnne can cuts at substantially right an les to each other. This adjustment of the plate 28 and routing units thereon, is effected by means of a crank 30 supported in bearing 31, and carrying a worm 32 meshing with a curved rack 33 fixed to plate 28.

The bearing 31 and the pivot post 29 are carried by a slide table mounted upon rails 35 and 36 extending along the table 2. Thus, the table 3e, and routing means supported thereon, may be slid along the table to suc cessively bring the routing machines in the different locations along the table necessary for cutting different riser and tread grooves in the stringers. This longitudinal adjust-- ment of table 3% is effected manually by means of a crank 37 carried by horizontal shaft 38 supported in bearings carried by table 3% and having a bevel gear 39 at its inner end meshing with a bevel gear 10, the bore of which is internally threaded to mesh with the thread on a fixed screw 41:1 extending longitudinally of and carried by frame 1. The adjustment of the routing mechanism along the table 2 is in uniform steps between routing ope ations, so that the tread channels are uniformly spaced apart.

In order to definitely measure such steps as required for different stairways, a cylinder 4-2 is supported horizontally at the front of the machine, beneath the table 2, and has trunnions extending into bearings 43. This cylinder is adjustable around its axis to bring dinerent rows of perforations id therein, in line with a spring plunger e5, carried by a supp'rt 46 therefor, depending from slide table 34. The cylinder l i when adjusted around its axis, is locked in adjusted position by a pin l7 carried by a bracket on frame 1 and adapted to enter holes 43 in the hub of he cylinder. Each horizontal row of perorations l lin cylinder 42 is employed for ..etermining the height of risers or the disanccs between treads of a stairway, accordg to the height of floor levels. The spacing in of one horizontal row of perforations varies from the next in fractions of an inch, such as 1/16 or 1/14, so that the stringers may be made exactly as required for different heights of stairways.

The cylinder is preferably marked to indicate which row of perforations are to be used for a given pitch and distance between floors, and likewise the table 3 1 is provided with a scale 19 to assist in determining the proper adjustment of the router mechanism, according to stair pitches.

When the machine is used for routing risers in which the width of treads is other than standard, it is preferable to provide adjustable stops 55 for limiting the motion of the router motors along the rods 12. In order that the routing tools at the lower end of the motor shafts may pass through the frame 16,,this frame is slotted, as indicated at 50, Fig. 1; and likewise the plate 28 which carries the routing units, has a slot as shown in 1, which is wider at one end than at the other to provide for the necessary movement of the tools in cutting the tapered channels 22 and 23. The channels not only receive the risers 52 and treads 53, but also the wedges 54, Fig. 8, for holding the same in place.

In the operation of this machine, the riser l is clamped to table 2, and the riser 7 is placed against the shoulder clamps 8, and the clamps 9 are swung downwardly into clamping position. The crank 30 is operated according to a given pitch of stairway as indicated by the scale 49. The cylinder l2 is set according to a table of values including pitch and height of stairway. Both motors are then pushed along the rods 12 toward the posts 17 and while the supporting frame therefor engages one of the pins'2 l; or 25, then the handles 21 are pressed laterally to cause the motor supportingframes to engage the oppositepin, and arepulled toward the operator, completing the cut. Next, the pin 4:5 is withdrawn from the perforation in the cylinder and the crank 37 is operated until the pin springs into the next perforation. The routing operation is repeated the required number of times at different locations on the stringers.

While but one specific embodiment of this invention has been herein shown and described, it will be understood that certain details of the construction shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

I claim:

1. In a routing machine, a frame structure, a plurality of routing units, support ing means for said routing units shiftably mounted upon said frame structure whereby said units may be simultaneously adjusted along said frame structure, angularly related guide means for each of said routing units whereby said units may be shifted angularly toward and away from each other, and each of said units being provided at its opposite ends with tool chucks.

2. In a routing machine, a frame structure, a work support thereon, a pair of routing units and supporting means for said routing units, means for shifting said routing unit supporting means along said frame structure, said routing unit supporting means including guide means for each routing unit, said guide means being arranged to permit the routing units to travel angularly with reference to each other, a pivotal support common to both of said guide means whereby the guide means may be angularly adjusted in unison.

3. In a routing machine, a frame structure, a work support on said frame structure, routing means comprising a pair of driven routing units, and means for supporting said units for movement at an angle to each other and for movement along said frame and for movement in unison angularly with reference to said work support.

4. In a routing machine, a frame structure arranged with oppositely disposed and spaced apart work supports, a pair of driven routing units located between the oppositely disposed work supports, each of said routing units including a shaft having tool chucks on each end whereby tools carried by said chucks may simultaneously operate on work carried by said spaced work supports, each of said routing units being provided with guide means along which the unit may be drawn while operating, and means for angularly adjusting the guide means with reference to the work support.

5. In a routing machine a frame structure, a relatively shiftable work support and routing means carried on said frame structure, and a cylinder mounted in said frame structure for rotary adjustment therein, said cylinder being formed to control the extent of relative movement of the work support and routing means according to the adjustment of said cylinder.

6. In a routing machine, a frame structure, a work support thereon, a pair of routing units and supporting means for said routing units, said routing unit supporting means including guide means for each routing unit, said guide means being arranged to permit the routing units to travel angularly with reference to each other, a pivotal support common to both of said guide means whereby the guide means may be angularly adjusted in unison, and mechanism for producing a relative shift between said work support and said routing unit supporting means including adjustable means for variably controlling the extent of said relative shift.

7. In a. routing machine, a frame struc ture arranged with oppositely disposed and spaced apart work supports, a pair of driven routing units located between the oppositelydisposed work supports,

Sept. 1930.

GEORGE MAOKAY.

each of said routing I units including a shaft having tool chucksy 

